Functionalized aluminum reagents

ABSTRACT

The invention is directed to functionalized aluminum reagents of formula 1 
                         
where R is a linear or branched alkane group containing 1 to 8 carbon atoms, and R 1  is phenylene, or a linear or branched alkane diyl group containing 2 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms; Q is of formula 2
 
                         
where R 3  and R 4  are independently phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or R 3  and R 4  taken together with the nitrogen atom represent a nitrogen containing heterocyclic group containing from 4 to 12 carbon atoms.

BACKGROUND

Coordinative chain transfer polymerization (CCTP) using main groupmetals, i.e., a reversible chain transfer of polymeryl chains betweenchain growth active metal centers and chain growth inactive metalcenters, has become an important strategy in insertion polymerization toreduce the amount of polymerization catalysts, to control the molecularweight and molecular weight distribution of polymers as well as tointroduce chain end-functionalization by appropriate quenching of maingroup metal polymeryls. See Valente et al., Chem. Rev. 2013, 113,3836-3857; Jian et al., Chem. Commun. 2010, 46, 3022-3024; German etal., Angew. Chem. Int. Ed. 2013, 52, 3438-3441. (b) Norsic et al.,Angew. Chem. Int. Ed. 2015, 54, 4631-4635; Makio et al., J. Am. Chem.Soc. 2013, 135, 8177-8180.

Most commonly, commercially available un-functionalized aluminum andzinc alkyls have been employed, with zinc alkyls much better performingin terms of transfer efficiency and thus molecular weight control. Withrespect to heteroatom-functionalized main group metal alkyls, recentlyhomoleptic di(ω-aminoalkyl) magnesium reagents have been used as chaintransfer reagents to yield end functionalized amino polyethylenylmagnesiums (Ottou et al., Macromolecules 2017, 50, 8372-8377).Functionalized magnesium reagents were also employed to initiatepolybutadiene chain growth to end-functionalized high transpolybutadiene (Leicht et al., Macromolecules 2018, 51, 763-770.), orwith increased chain transfer numbers, to functionalized polybutadienesof less uniform stereochemistry (WO201013945).

In contrast, both in organic synthesis and in polymer chemistry,heteroatom-functionalized aluminum reagents have scarcely been used assynthetically useful reactants for the transfer of functional groupsubstituted carbon nucleophiles probably owing to drawbacks in thesynthesis of homoleptic aluminum alkyls or the expectedly lowchemoselectivity of mixed aluminum alkyls (Xu et al., Acc. Chem. Res.2016, 49, 2158-2168; Gao et al., J. Am. Chem. Soc., 2010, 132,10961-10963; May et al., Org. Lett., 2011, 13, 3040-3043.)

SUMMARY

The present invention is directed to functionalized aluminum reagents offormula 1

where R is a linear or branched alkane group containing 1 to 8 carbonatoms, and R¹ is phenylene, or a linear or branched alkane diyl groupcontaining 2 to 10 carbon atoms, or a combination of one or morephenylene groups and one or more linear or branched alkane diyl groupscontaining 1 to 10 carbon atoms; Q is of formula 2

where R³ and R⁴ are independently phenyl or a linear or branched alkylgroup containing 1 to 10 carbon atoms, or R³ and R⁴ taken together withthe nitrogen atom represent a nitrogen containing heterocyclic groupcontaining from 4 to 12 carbon atoms.

The invention is further directed to a method of making functionalizedaluminum reagents.

DESCRIPTION

There are disclosed functionalized aluminum reagents of formula 1

where R is a linear or branched alkane group containing 1 to 8 carbonatoms, and R¹ is phenylene, or a linear or branched alkane diyl groupcontaining 2 to 10 carbon atoms, or a combination of one or morephenylene groups and one or more linear or branched alkane diyl groupscontaining 1 to 10 carbon atoms; Q is of formula 2

where R³ and R⁴ are independently phenyl or a linear or branched alkylgroup containing 1 to 10 carbon atoms, or R³ and R⁴ taken together withthe nitrogen atom represent a nitrogen containing heterocyclic groupcontaining from 4 to 12 carbon atoms.

There is further disclosed a method of making functionalized aluminumreagents.

Functionalized aluminum reagents of formula 1 and 2 may be produced byreaction of a compound of formula 3 with a dialkyl aluminum hydride offormula 4

where R⁵ is phenylene, or a linear or branched alkane diyl groupcontaining 1 to 9 carbon atoms, or a combination of one or morephenylene groups and one or more linear or branched alkane diyl groupscontaining 1 to 10 carbon atoms, and R is as previously defined.

The reaction of the compounds of formulas 3 and 4 may be done neat at atemperature ranging from 25 to 75 C for 12 to 36 hours. Optionally, thereaction may proceed in a hydrocarbon solvent in the presence of aneodymium (III) catalyst.

In one embodiment, the compound of formula 4 is diisobutyl aluminumhydride (DIBAL-H).

In various embodiment, the functionalized aluminum reagent of formula 1may be one of the following compounds 1a-1l.

The functionalized aluminum reagents are useful, for example, asactivators for lanthanide-based catalysts in polymerization ofconjugated dienes.

The invention is further illustrated by the following non-limitingexamples.

Example 1 (3-Diphenylaminopropyl)diisobutyl Aluminum (1a)

N,N-Diphenyl-N-allylamine (418 mg, 2 mmol), DIBAL-H (327 mg, 2.3 mmol),Nd(versatate)₃ (163 mg solution in hexanes, 100 μmol, 5 mol %), and 92mg C₆D₆ were combined in an 8 mL screw-cap vial and stirred for 14 h at323 K. The resulting solution contains 1 μmol Nd and ca 20 μmol of(3-Diphenylaminopropyl)diisobutyl aluminum (1a) per 10 mg solution andwas used without further purification.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 7.06 (m, 4H, 2- and 6-H), 6.93 (m, 4H,3- and 5-H), 6.83 (m, 2H, 4-H), 3.02 (t, ³J_(HH)=6.0 Hz, 2H, 7-H₂), 2.03(n, ³J_(HH)=6.6 Hz, 2H, 2×(CH₃)₂CHCH₂Al), (1.76 (m, 2H, 8-H₂), 1.18 (d,³J_(HH)=6.6 Hz, 12H, 2×(CH₃)₂CHCH₂Al), 0.53 (m, 2H, 9-H₂), 0.11 (d,³J_(HH)=6.6 Hz, 4H, 2×(CH₃)₂CHCH₂Al). ¹³C NMR (100 MHz, C₆D₆, 300 K): δ149.84 (C_(q), C1), 129.04 (CH, C3 and C5), 126.56 (CH, C4), 124.80 (CH,C2 and C6), 60.51 (C7), 28.69 (2×(CH₃)₂CHCH₂Al), 27.13(2×(CH₃)₂CHCH₂Al), 24.90 (2×(CH₃)₂CHCH₂Al), 22.04 (C8), 3.75 (C9).

Example 2 (5-Diphenylaminopentyl)diisobutyl Aluminum (1b)

N,N-Diphenyl-N-pent-4-enylamin (475 mg, 2 mmol), and DIBAL-H (291 mg,2.05 mmol) were combined in a 8 mL screw-cap vial and stirred for 14 hat 323 K after which 1b had formed in ca 93% along with traces ofisobutene.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 7.11 (m, 4H, 3- and 5-H), 7.01 (m, 4H,2- and 6-H), 6.83 (m, 2H, 4-H), 3.54 (t, ³J_(HH)=7.3 Hz, 2H, 7-H₂), 1.95(m, 2H, 2×(CH₃)₂CHCH₂Al), (1.63 (m, 2H, 8-H₂), 1.49 (m, 2H, 10-H₂), 1.31(m, 2H, 9-H₂), 1.03 (d, ³J_(HH)=7.2 Hz, 12H, 2×(CH₃)₂CHCH₂Al), 0.3 (br,6H, 11-H₂ and 2×(CH₃)₂CHCH₂Al). ¹³C NMR (100 MHz, C₆D₆, 300 K): δ 148.72(C6), 129.51 (C3 and C5), 121.91 (C4), 121.42 (C2 and C6), 53.23 (C7),33.13 (C9), 28.27 (2×(CH₃)₂CHCH₂Al), 27.21 (C8), 26.43(2×(CH₃)₂CHCH₂Al), 25.56 (C10), 23.99 (br, 2×(CH₃)₂CHCH₂Al), 11.52 (br,C11).

Example 3 (3-(9H-carbazol-9-yl)propyl)diisobutyl Aluminum (1c)

N-Allylcarbazole (2073 mg, 10 mmol), and DIBAL-H (1500 mg, 10.5 mmol)were combined in a 8 mL screw-cap vial and stirred for 16 h at 323 Kafter which 1c had formed >95% along with traces of isobutene. 1c wasalternatively prepared within 24 h at 298 K in the presence of 5 mol %Nd(versatate)₃.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 7.68 (m, 2H, 2-H), 7.19 (m, 2H, 4-H),7.09 (m, 4H, 3- and 5-H), 3.40 (t, ³J_(HH)=6.6 Hz, 2H, 7-H₂), 1.80 (m,2H, 8-H₂), 1.71 (m, 2H, 2×(CH₃)₂CHCH₂Al), 0.91 (d, ³J_(HH)=6.4 Hz, 12H,2×(CH₃)₂CHCH₂Al), 0.06 (m, 2H, 9-H₂), −0.16 (m br, 4H, 2×(CH₃)₂CHCH₂Al).¹³C NMR (100 MHz, C₆D₆, 300 K): δ 145.30 (C1), 126.68 (C4), 126.43 (C6),122.17 and 112.85 (C3 and C5), 120.71 (C2), 53.88 (C7), 28.24(2×(CH₃)₂CHCH₂Al), 26.24 (2×(CH₃)₂CHCH₂Al), 25.92 (C8), 24.40(2×(CH₃)₂CHCH₂Al), 8.36 (C9).

Example 4 (5-(9H-carbazol-9-yl)pentyl)diisobutyl Aluminum (1d)

N-Pent-4-enylcarbazole (1177 mg, 5 mmol), and DIBAL-H (780 mg, 5.48mmol) were combined in a 8 mL screw-cap vial and stirred for 16 h at 323K after which 1d had formed >95% along with traces of isobutene. 1d wasalternatively prepared within 4 h at 343K, or within 24 h at 298K inpresence of 5 mol % Nd(versatate)₃.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 8.01 (m, 2H, 2-H), 7.37 (m, 2H, 4-H),7.18 (m, 4H, 3- and 5-H), 3.81 (t, ³J_(HH)=6.8 Hz, 2H, 7-H₂), 1.90 (m,2H, 2×(CH₃)₂CHCH₂Al), 1.56 (m, 2H, 8-H₂), 1.22 (m, 2H, 10-H₂), 1.14 (m,2H, 9-H₂) 1.02 (d, ³J_(HH)=6.4 Hz, 12H, 2×(CH₃)₂CHCH₂Al), 0.21 (m, 4H,4H, 2×(CH₃)₂CHCH₂Al), 0.35 (m br, 11-H₂). ¹³C NMR (100 MHz, C₆D₆, 300K): δ 140.93 (C1), 125.90 (C4), 123.48 (C6), 120.79 (C2), 119.14 and109.06 (C3 and C5), 42.92 (C7), 33.23 (C9), 28.73 (C8), 28.26(2×(CH₃)₂CHCH₂Al), 26.30 (2×(CH₃)₂CHCH₂Al), 25.37 (C10), 24.8 (v br,2×(CH₃)₂CHCH₂Al), 12.12 (C11).

Example 5 (3-(10H-phenothiazin-10-yl)propyl)diisobutyl Aluminum (1e)

N-Allylphenothiazin (1197 mg, 5 mmol), and DIBAL-H (700 mg, 4.92 mmol),and C₆D₆ (603 mg) were combined in a 8 mL screw-cap vial and stirred for16 h at 323 K after which 1d had formed >90%. The resulting solutioncontains 20 μmol 1e per 10 mg solution.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 7.07, 6.87, and 6.69 (m:m:m, 2:2:4H,2-H to 5-H), 3.45 (t, ³J_(HH)=5.2 Hz, 7-H₂), 2.00 (m, 2H, 8-H₂), 1.80(m, 2H, 2×(CH₃)₂CHCH₂Al), 1.02 (br, 12H, 2×(CH₃)₂CHCH₂Al), 0.24 (t,³J_(HH)=6.8 Hz, 9-H₂), −0.03 (br, 2×(CH₃)₂CHCH₂Al). ¹³C NMR (100 MHz,C₆D₆, 300 K): δ 146.02 and 122.78 (C1 and C6), 128.92, 128.24, 124.77,and 118.41 (C2-C5), 53.80 (C7), 28.49 (2×(CH₃)₂CHCH₂Al), 26.93(2×(CH₃)₂CHCH₂Al), 25.18 (2×(CH₃)₂CHCH₂Al), 24.70 (C8), 8.93 (C9).

Example 6 (3-(1H-indol-1-yl)propyl)diisobutyl Aluminum (1f)

N-Allylindol (1572 mg, 10 mmol), and DIBAL-H (1480 mg, 10.4 mmol) werecombined in a 8 mL screw-cap vial and stirred for 16 h at 323 K afterwhich 1f had formed >95%.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 7.51, 7.14, and 7.05 (m each, 1:1:2H,2-H to 5-H), 6.67 and 6.42 (br each, 1:1H, 7-H and 8-H), 3.43 (m br, 2H,9-H₂), 1.79 (m br, 2H, 2×(CH₃)₂CHCH₂Al), 1.59 (m br, 10-H₂), 0.98 (d,³J_(HH)=6.4 Hz, 12H, 2×(CH₃)₂CHCH₂Al), −0.09 (br, 6H, 11-H₂ and2×(CH₃)₂CHCH₂Al). ¹³C NMR (100 MHz, C₆D₆, 300 K): δ 139.08 and 129.96(C1 and C6), 126.48 and 105.28 (C7 and C8), 124.80, 122.45, 121.28, and110.93 (C2-C5), 50.83 (C9), 28.30 (2×(CH₃)₂CHCH₂Al), 26.38(2×(CH₃)₂CHCH₂Al), 26.13 (C10), 24.51 (2×(CH₃)₂CHCH₂Al), 9.82 (C11).

Example 7 (5-(1H-indol-1-yl)pentyl)diisobutyl Aluminum (1g)

N-Pent-4-enylindol (927 mg, 5 mmol), and DIBAL-H (720 mg, 5.06 mmol)were combined in a 8 mL screw-cap vial and stirred for 16 h at 323 Kafter which 1g had formed >95%.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 7.69 and 7.17 (m each, 1:3H, 2-H to5-H), 6.90 and 6.45 (br each, 1:1H, 7-H and 8-H), 3.61 (m, 2H, 9-H₂),1.92 (m, 2H, 2×(CH₃)₂CHCH₂Al), 1.54 (m, 2H, 10-H₂), 1.28 (m br, 2H,12-H₂), 1.14 (m br, 2H, 11-H₂), 1.05 (d, ³J_(HH)=6.8 Hz, 12H,2×(CH₃)₂CHCH₂Al), 0.20 (m br, 4H, 2×(CH₃)₂CHCH₂Al), −0.06 (m br, 2H,13-H₂). ¹³C NMR (100 MHz, C₆D₆, 300 K): δ 137.10 and 129.66 (C1 and C6),130.85 and 97.85 C7 and C8), 122.40, 121.74, 120.39, and 110.12 (C2-C5),46.63 (C9), 33.02 (C11), 29.75 (C10), 28.37 (2×(CH₃)₂CHCH₂Al), 26.48(2×(CH₃)₂CHCH₂Al), 25.54 (C12), 24.59 (2×(CH₃)₂CHCH₂Al), 11.65 (C13).

Example 8 (3-(3-methyl-1H-indol-1-yl)propyl)diisobutyl Aluminum (1h)

N-Allyl-3-methylylindol (856 mg, 5 mmol), and DIBAL-H (720 mg, 5.06mmol) were combined in a 8 mL screw-cap vial and stirred for 16 h at 323K after which 1g had formed >95%.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 7.33, 7.09, and 7.05 (m each, 1:1:2H,2H to 5-H), 6.37 (s, 1H, 8-H), 3.31 (t, ³J_(HH)=6.2 Hz, 9-H₂), 2.06 (s,3H, 12-H₃), 1.79 (m br, 2H, 10-H₂), 1.71 (m br, 2H, 2×(CH₃)₂CHCH₂Al),0.91 (d, ³J_(HH)=6.8 Hz, 12H, 2×(CH₃)₂CHCH₂Al), 0.11 (m br, 2H, 11-H₂),−0.20 (m br, 4H, 2×(CH₃)₂CHCH₂Al). ¹³C NMR (100 MHz, C₆D₆, 300 K): δ141.96 and 131.60 (C1 and C6), 124.6, 121.89, 120.43, and 112.47 (cC2-C5and C8), 109.7 (C7), 52.44 (C9), 28.37 (2×(CH₃)₂CHCH₂Al), 26.40(2×(CH₃)₂CHCH₂Al), 25.80 (C10), 23.73 (2×(CH₃)₂CHCH₂Al), 9.98 (C12),8.77 (C11).

Example 9 (3-(indolin-1-yl)propyl)diisobutyl Aluminum (1i)

N-Allylindolin (796 mg, 4 mmol) and DIBAL-H (595 mg, 4.18 mmol) werecombined in a 8 mL screw-cap vial and stirred for 16 h at 343 K afterwhich 1i had formed >90%. Due to coordination of aluminum to thenitrogen atom, 7-11-CH₂ exhibit diastereotopic protons, likewise the iBugroups become fully diastereotopic.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 6.94 and 6.87 (m each, 1:2H, 3-, 4-,and 5-H), 6.78 (m, 1H, 2-H), 3.54 and 2.24 (m each, 1:1H, 8-H₂), 3.06and 2.24 (m each, 1:1H, 9-H₂), 2.79 and 2.42 (m each, 1:1H, 7-H₂), 1.98and 1.61 (m each, 1:1H, 10-H₂), 1.98 and 1.76 (2×(CH₃)₂CHCH₂Al), 1.10,1.06, 0.99, and 0.86 (d each, ³J_(HH)=6.4 Hz, 12H, 2×(CH₃)₂CHCH₂Al),0.29 (m, 2H, 11-H₂), −0.06 and −0.25 (m each, 2:2H, 2×(CH₃)₂CHCH₂Al).¹³C NMR (100 MHz, C₆D₆, 300K): δ 149.11 (C1), 133.52 (C6), 127.26,125.71, and 125.24 (C3-C5), 117.06 (C2), 63.03 (C9), 57.97 (C8), 28.87,28.84, 28.78, 28.74, and 28.41 (2×(CH₃)₂CHCH₂Al and C7), 27.27 and 26.92(2×(CH₃)₂CHCH₂Al), 23.51 (C10), 23.41 and 23.06 (2×(CH₃)₂CHCH₂Al), 4.58(C11).

Example 11 (3-(phenyl(trimethylsilyl)amino)propyl)diisobutyl Aluminum(1k)

N-Allyl-N-phenyl-N-trimethylsilyamine (1097 mg, 5 mmol), DIBAL-H (782mg, 5.5 mmol), Nd(versatate)₃ (407 mg solution in hexanes, 250 μmol),and 214 mg C₆D₆ were combined in a 8 mL screw-cap vial and stirred for16 h at 343 K after which 1k had formed ca 95%. The solution contains 1μmol Nd and ca 20 μmol 1k per 10 mg solution.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 6.95 and 6.85 (m each, 4:1H, 2-H to5-H), 2.98 (t, ³J_(HH)=6.4 Hz, 7-H₂), 2.05 (m, 2H, 2×(CH₃)₂CHCH₂Al),1.91 (m, 2H, 8-H₂), 1.16 (d, ³J_(HH)=6.4 Hz, 2×(CH₃)₂CHCH₂Al), 0.39 (m,2H, 9-H₂), 0.22 (m br, 4H, 2×(CH₃)₂CHCH₂Al), −0.02 (s, 9H, TMS). ¹³C NMR(100 MHz, C₆D₆, 300K): δ 145.75 (C1), 128.37, 125.48, and 124.99(C2-C5), 54.74 (C7), 28.75 (2×(CH₃)₂CHCH₂Al), 27.21 (2×(CH₃)₂CHCH₂Al),26.00 (2×(CH₃)₂CHCH₂Al), 23.13 (C8), 3.28 (C9), 0.18 (TMS).

Example 12 (3-(pyrrolidin-1-yl)propyl)diisobutyl Aluminum (1l)

N-Allylpyrrolidin (556 mg, 5 mmol), DIBAL-H (740 mg, 5.2 mmol),Nd(versatate)₃ (163 mg solution in hexanes, 100 μmol, 2 mol %) werecombined in a 8 mL screw-cap vial and stirred for 20 h at 343 K afterwhich 1j had formed in ca 95%. Due to coordination of aluminum to thenitrogen atom, 1- and 2-CH₂ as well as (CH₃)₂CHCH₂Al exhibitdiastereotopic protons.

¹H NMR (400 MHz, C₆D₆, 300 K): δ 2.85 and 1.84 (m each, 2:2H, 2×1-H₂),2.17 (t, ³J_(HH)=6.0 Hz, 3-H₂), 1.95 (2×(CH₃)₂CHCH₂Al), 1.60 (m, 2H,4-H₂), 1.48 and 1.34 (m each, 2:2H, 2×2-H₂), 1.08 (d, 3J_(HH)=7.6 Hz,2×(CH₃)₂CHCH₂Al), 0.133 (t, ³J_(HH)=7.6 Hz, 5-H₂), −0.03 and −0.12 (ddeach, ²J_(HH)=14.0 Hz, ³J_(HH)=7.6 Hz, 2×(CH₃)₂CHCH₂Al). ¹³C NMR (100MHz, C₆D₆, 300K): δ 62.55 (C3), 54.98 (C1), 28.96 (2×(CH₃)₂CHCH₂Al),27.35 (2×(CH₃)₂CHCH₂Al), 24.00 (C4), 23.00 (2×(CH₃)₂CHCH₂Al), 22.86(C2), 4.66 (C5).

The invention claimed is:
 1. A functionalized aluminum reagent offormula 1

wherein R is a linear or branched alkane group containing 1 to 8 carbonatoms, and R¹ is phenylene, or a linear or branched alkane diyl groupcontaining 2 to 10 carbon atoms, or a combination of one or morephenylene groups and one or more linear or branched alkane diyl groupscontaining 1 to 10 carbon atoms; Q is of formula 2

wherein R³ and R⁴ are independently phenyl or a linear or branched alkylgroup containing 1 to 10 carbon atoms, or R³ and R⁴ taken together withthe nitrogen atom represent a nitrogen containing heterocyclic groupcontaining from 4 to 12 carbon atoms; wherein the functionalizedaluminum reagent of formula 1 is selected from the group consisting of

wherein TMS is a trimethylsilyl group.
 2. The functionalized aluminumreagent of claim 1 selected from the group consisting of structures 1aand 1b.
 3. The functionalized aluminum reagent of claim 1 selected fromthe group consisting of structures 1c and 1d.
 4. The functionalizedaluminum reagent of claim 1 having the structure 1e.
 5. Thefunctionalized aluminum reagent of claim 1 selected from the groupconsisting of structures 1f, 1g, 1h and 1i.
 6. The functionalizedaluminum reagent of claim 1 selected from the group consisting ofstructures 1j and 1k.
 7. The functionalized aluminum reagent of claim 1having the structure 11.